Sodium Hydroxide IS a “Lye”, but Lye is not always “Sodium Hydroxide”.
Every soap on the planet must use a “Lye” or “Caustic” agent or you can’t make soap, period. The word “Lye” is sort of used like we use the word Xerox to describe any photo type duplication of a document. People ask, “Is there lye in your soap?” And the answer is, “No, there is no lye left in our soap - no lie. But, yes we did use lye to make vegetable oils turn into beautiful soap and the type of lye we used was sodium hydroxide.” Sodium hydroxide is a simple ionic compound of sodium with a hydroxide ion - a negatively charged combination of single oxygen and hydrogen atoms. Soap, at the chemical level, in its simplest form without all the smells and subtleties, is a salt created from a fatty acid. Simply put, sodium hydroxide converts the “acids" in oils to create a sodium salt - aka, Soap - which is a salt. You got this, right? These salts act as surfactants, substances that reduce the surface tension in liquids. They form tiny balls around particles of grease, stopping the grease from being hydrophobic and allowing it to dissolve and be carried away by water.
Let's re-write the above paragraph:
Soap is actually considered a Salt. Soap is created when you combine oils or fat (acid, actually) and lye (the base). (And, remember, the “base” we use is sodium hydroxide and "it's all about da base":) When you combine those two - acid and a base, you create a new compound - yep, soap! Soap then makes dirt and grease slippery, and makes that gunk slide off your skin. Sodium Hydroxide is widely used in many things today. It is used in steps for peeling fruits and vegetables to feed our massive population, for processing cocoa and chocolate (thank the stars!), for thickening ice cream and soda processing. Olives are soaked in sodium hydroxide along with other substances to make them black, and soft pretzels are also coated with the compound to give them a chewy texture. Plastic, rayon and textile industries use sodium Hydroxide. The paper making industry also uses the stuff. Seems like Sodium Hydroxide might be important to 21st century living, eh?
Now, if someone tells you they don’t use lye to make their handmade natural artisan soap, or prefer to use a “no lye” soap, well, that just can’t be done and you should refer them here to this page. Soap IS: acid + lye = soap. Sometimes, and I am sure it's not intentional fibber-mageeing, someone might say they make a non lye soap and are referring to either a glycerin "melt and pour" (which I cover here) or they buy soap "noodles" (and somewhere in soap noodle heaven lye had to be used to make the noodles) melt them down and form bars and say they do not make lye soap. Well, first of all, Glycerin "melt and pour" is glycerin, and not really soap at all, but rather a by-product of soap. You would be really surprised at how loosely the term "soap" is used by companies and individuals who make a "melt and pour" product and try and make it NOT look like "melt and pour", but rather work very hard to make their product look like, well, like our cold processed, totally from scratch, real honest to goodness soap. And, second of all, don't believe everything you read on the internet, unless it's here at EarthlyDelightSoap.com - we're like Superman, we never lie, we just use lye. Oh, my!
Natural handmade (real) soap, when made correctly, contains no lye, it's turned to soap. Real soap leaves the skin soft and supple because it actually rinses off the skin and allows your skin to breath. If you can pronounce everything that is used to make a product, I think common sense just has to tell you it’s good for you, eh?
P.S. I know I use the term "eh" twice on this page. No, I am not from Canada - as I've been asked many times - but I did grow up in Detroit and lived in metro Detroit until I was 48 or so, and believe I picked up the slang "eh" from there. Just FYI